Indication apparatus



Aug. s, 1944.

' E. M. ALLEN INDICATION APPARATUS Filed Oct. 9, 1942 llllll Patented Aug. 8, 1944 -UNITED STATES PATENT OFFICE Y INDICATION APPARATUS Earl M. Allen, Swissvale, Pa., assignor to The` Union Switch & SignalCompany, Swissvale, Pa., a corporation of Pennsylvania Application october 9, 1942, serial Nov.,4f:1,3'z9` 6 claims. (c1. 246-122) My invention relates to indication apparatus, and more particularly to indication apparatus for railway signal systems. d

Arailwaysignal system governing a track layout sometimes includes means for providing indications for the diiferent signals, switches and track sections of the layout. These indications may be visual or audible, r both, and are usually given at the oiiice in which there is located an operator who controls theA switches land signals, line circuits being used to transmit the indications to the oice. Such oflice may be, and frequently is, a relatively long distance from the location of the track layout, and it is in the interest of simplicity and economy if a plurality or different indications can be transmitted over a single line circuit.

Accordingly, a feature of my invention is the provision of no vel and improved apparatus wherewith a plurality of different indications are transmitted over a single line circuit consisting of two line wires, one wire of which may be a wire common to a plurality of circuits. Other features, objects and advantages of my invention will appear as the specification progresses.

I provide four different indications over a single line circuit by using four different forms of current. Steady or non-coded current of positive polarity provides a rlrst indication, momentary current of positive polarity followed by coded current alternately positive and negative in polarity provides a second indication, steady or no necodedurrent of negative polarity provides a `third indication, and momentary current of negative polarity followed'by coded current alternately positivey and negative in polarity provides a fourth indication. These four forms of current are supplied one at a time to a line circuit according to preselected conditions of the devices tobe indicated, and the currentris received at the receiving point or oice by indication means characterized to respond differently to the polarity ofthe current and to the coded and non-coded 'conditions ci the current. Such indication vmeans is used to selectively control visual or audible indicators.

I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form of apparatus embodying my invention when used to indicate the positions of the signals and the traflic conditions of a detector track circuit associated with a railway switch. It is to be understood, however, that my invention is not limited to use with these particular devices, but this one application serves to illustrate the many places where apparatusembodying my invention is useful. l

Referring to the drawing, the diagram` at the upper right-hand portion of the drawing repre-l sents a stretch of railway track D-E- which includes a track switch SW leading to a second track F. The track switch SW may be hand operated or power operated, or it may be a so-called spring switch. The trackrails at this switch location are formed by the usual insulated rail joints with a detector track section IT, and which, section is provided with a track circuit including a track relay ITR, the relationship of relay ITR to the track circuit beingindicated in the drawing by-a dotted Aline l0. Track relay ITR controls, in turn, a slow release repeater relay ITP, this latter relay beingenergized by an obvious circuit including front contact Il of rtrack relay ITR.

Three signals 2S, 4S and GS are associated with the switch SW in the usual arrangement for governing traic. Signal 2S governs tramo mov.- ing from right to left on track D-E, signalAS governs traiiic moving from track F to the track D-E, and signal GS is provided with a top and a lower mechanism which govern traflic from left to right on track D--E and from track D-E to track F, respectively. These signals may be of any standard form and are shown convene tionally only. Itis suicient to point out that each of these signals is operable to display a stop indication and a proceed indication, eachvsignal being normally set to display its stop indication as illustrated in the drawing. The apparatus for controlling these signals is not shown, since such control apparatus forms no part of my invention and it would be of any standard arrangement.

It is contemplated, however, that the signals would be governed in part at least by an voperator located at a remote ofce designatedbythe reference character OF, control being effected by the operator through the medium of arremete control system, several of such systems being well-known to theart. u f

Each of these signals has'associated therewith a signalrepeater relay which is governed according to the aspect vof the signal, and each signal repeater relay is energized when and only when the associated signal displays its stop indication. These signal repeater relays are designated'by the reference character GP, vwith a numeral prex corresponding to the numeral of the associated signal, and the relationship of A source of direct current, such as battery FB i I is provided at the switch station. Battery FB is preferably of. the so-called split battery type having a positive terminal B, a negative terminal N and a mid terminal C. The apparatus at the station also includes a coder CD which is shown as being of the relay type, the arrangement being` such that a contact member 15 of the coder is operated to alternately engage contacts 15a and 15b as long as a winding I3 of the coder is supplied with current from a suitable source, such as battery FB. The rate at which contact member 15 is operated is preselected and may be, for example, 75 operations per minute.

A line circuit extends from the switch station to the oice OF, this line circuit consisting of two line wires LI and COM. The line wire COM may be a common wire used with other circuits and is connected to the mid terminal C of battery FB. The manner of supplying four different forms of current from battery FB to the line circuit according to the different positionsv of the signals and traffic conditions of section IT will appear when the operation of the apparatus is described.

'I'he oilice apparatus includes receiving means and a plurality of indicators, the receiving means being such as to distinguish between the polarity of the current supplied thereto and between coded andnon-coded conditions of the current. This receiving means may take any one of several diierent forms, and as shown it comprises two indication relays 2GK and SGK, a rectifying unit RC, a polar relay GKP and a slow acting relay GKPP. The indication relays 2GK and SGK are neutral relays connected to the line circuit through the rectifier unitrRC. One terminal of a winding of each of the relays 2GK and SGK is relay 2GK and only current of the other polarity i is passed to relay SGK. I shall assume by way of illustration that relay 2GK is energized only by current of positive polarity and relay SGK is energized only by current of negative polarity. Two asymmetric units I1 and I8 of the unit RC are preferably connected across the windings of relays 2GK and SGK, respectively, to provide these relays With a slow to release characteristic. As will appear hereinafter, each relay 2GK and SGK is provided with a slow release period slightly greater than the half code period of the coder CD at the station.

Relay GKP is a polar relay characterized by its armature I9 remaining vin the position to which it was last moved whenr the relay is deenergized. Relay GKP is controlled by the two indication relays, the arrangement being that when relay 2GK is picked up and relay SGK is released, current flows from terminal B of an oflice battery OB through front contact 2| of relay 2GK, winding 20 of relay GKP and back contact 22 of relay SGK to terminal N of battery OB, andrelay GKP is then energized by current of normal polarity to operate its armature I9 to a normal or right-hand position to close normal polar contact Iii-23; and when relay SGK is picked up and relay 2GK is released current ows from battery terminal B through front contact 24 of relay SGK, winding 20 of relay GKP and back contact 25of relay 2GK to terminal N, and

' polar relay vGKP is then energized by current of Y reverse polarity to operate its polar armature to a reverse'or left-hand position to close reverse polar contact I9-2S.

Relay GKPP is a neutral relay provided with preselected slow pick-up and slow release periods. This relay is also controlled by the two indication relays, current being supplied to relay GKPP from battery OB either by a circuit including front contact 21 of relay 2GK and back contact 28 of relay SGK, or by a ,circuit including front contact 29 of relay SGK and back contact 30 of relay 2GK. Thus relay GKPP is energized when either one of theV two indication relays is picked up, and is deenergized when both indication relays are released and 4when both indication relays are picked up.

The office relays controlvisual indicators including four lamps 2L, 4L, SL and ITL for indicating signals 2S, 4S and SS, and track section IT, respectively. The manner of controlling these indicator lamps by the oflce relays will appear presently.

In describing the operation of the apparatus, Ishall rst assume that signal 2S is moved to its proceed position to permit a train to move from right to left on track D-E. Signal repeater relay 2GP is then deenergized and indication current of positive polarity flows from terminal B of. battery FB through back contact 3| of relay 2GP, front contacts 32, 33 and 34 of relays IGP, SGP and ITR, respectively, line wire LI, asymmetric unit I5 in its forward direction, winding of relay 2GK, wire I4 and common return wire to terminal C of battery FB. This indication current energiz'es relay 2GK and that relay is picked up closing front contacts 2| and 21. With front contact 2I closed, ,polar relay GKP is energized with current of normal polarity to close its normalpolar contact Ill-23, and with front contact21 closed, relay GKPP is energized and picked `up at the-end of its slow pick-up period. A circuit for lamp 2L is now formed from terminal B of battery OB through front contact 35 of relay 2GK, back contact 3S of relay SGK, lamp 2L, front contact 31 of relay GKPP, and normal polar contact I9-23 of relay GKP to terminal N of the battery, so that-lamp 2L is illuminated to indicate the proceed indication position of signal 2S. Thus steady or non-coded indicationcurrent of positive polarity is applied to the line circuit to indicate'the proceed indication of signal 2S. l 1

l `When the train advances to the left and enters section IT, the track relay ITR is shunted to cause signal 2S to be returned to its stop indication in the usual well-known manner. This operation of signal 2S causes relay 2GP to be reenergized.U The release of track relay ITR to open front contact 34 discontinuesthe supplyof indication current of positive polarity, and indication relay ZGK at the oce is deenergized and released at the end of its slow release period. When track relay ITR is released, front contact I I is opened and repeater relay ITP is deenergized and releases at the end of its predetermined slow release period. During the slow release period of relay ITP, current of negative polarity news from'terminal C of battery FB through line wire COM, wire I4, winding of indication relay SGK, asymmetric unit IS in its forward direction, line wire LI, back contact 38 of relay ITR, and frontcontact 3S of relay ITP to terminal N of battery FB, and indication relay SGK is energized. The picking up of relay SGK to'open back Contact 3S causes lamp 2L to be extinguished. The opening of back contact 28 of relay SGK causes relay GKPP to bedeenergized .but relay GKPP remains picked up due to its slow release characteristic. The slow release period of relay ZGK is short as compared to the slow release period of relay ITP and consequently relay ZGK releases While relay SGK is energized by current of negative polarity. With relay 2GK released and relay SGK picked up, polar relay GKP is energized at reverse polarity to close reverse polar contact I3-26, and the energization of relay GKPP is reversed causing relay GKPP to release at once. It is to be observed that no false illumination of indicator'rlamp 4L results during the slow release period ofrelay ZGK be# cause relay GKPP is held picked up due to its slow release characteristic. The slow release period of repeater relay ITP is long enough to assure release of relay ZGK and operationof polar relayGKP but is less than the Dick-up period of relay GKPP, and hence before relay GKPP is pickedup due to this reverse energization, the relay ITP releases to open front contact 39 and discontinue the supply of indication current of negative polarity. With both track relay ITR and its repeater relay ITP released, the indication current is codedto be alternately positive and Ai, negative in polarity by action of the coder CD,

the positive terminal B of battery FB being connected to line wire LI through coder contact 'I5-15a and back contacts 4S and 38 of relays ITP and I TR, respectively, and the negative terminal N of the battery being connected to the line wire LI through coder contact I5-ISD and back contacts 4S and 38. With the indication current thus coded to be alternately positive and negative in polarity, the two indication relays z 2GK and SGK are alternately energized and both areV held picked up because the slow release period of each relay 2GK and SGK is slightly greater than the half code period of coder CD. With both indication relays ZGK'and SGK picked up, relays GKP and "GKPP are both deenergized. A circuit is now formed from terminal B of battery OB through front contact 35 of relay ZGK, front contact 4I of relay SGK, lamp ITL, back contact 42 of relay GKPP and reversepolar contact I92S of relay GKP to terminal N, and the lamp IL is illuminated to indicate the occupancy of section IT. Thus occupancy of'section IT is indicated by an indication current that is of negative polarity for a predetermined interval and then coded to be alternately positive and negative in polarity.

When this train vacates section IT, the track relay ITBI ispicked upto discontinue the supply of indication current, with the result that the indication lamp 'I TL becomes dark, and the apparatus is restored to its normal condition.

Assuming signal SS is operated to its proceed indication position to permit a train to move from the left to the right on track D-E, the relay SGP is deenergized and indication current flows from terminal C over the common line Wire COM, wire I4,'winding of relay SGK, asymmetric unit IS in its forward direction, line wire LI, front contact 34 of relay ITR, and back contact y43 of relay SGP to terminal N of battery FB, and indication'relay SGK is energized. With relay SGK picked up to close front contacts 24 and `23, polar relay GKP is energized with current ofV reverse polarity to close its reverse polar contact I9--2S if that contact is not already closed, and relay GKPP is energized and picked up at the end of its slow pick-up period. .A circuit is now formed from terminal B of battery OB through back contact 44 of relay 2GK, front Contact 45 of relay SGK, lamp SL, front contact 4S of relay GKPP, and reverse polar contact ISI-2S of relay GKP to terminal N, and lamp SL is illuminated to indicate the proceed indication of signal SS. Thus signal SS is indicated by steady or noncoded indication current of negative polarity.

When the train enters section IT and shunts track relay I TR, the signal SS is restored to its stop indication and relay SGP is energized. When the track relay lI'I'R is deenergized, the repeater relay ITP is also deenergized and releases at the end of its slowrelease period. During the slow release period of repeater relay ITP, indication current of negative polarity is still supplied to the line lcircuit through front contact-l of relay ITP- and back contact 3S of relay ITR and then upon the release of repeater relay ITP to close backccntact 40 the circuit is completed through the coder contacts and the indication current is coded to be alternately positive and negative in polarity. When the current is thus coded both relays ZGK and SGK are energized and relays GKP and GKPP are deenergized with the result that the indication lamp SL is extinguished and lamp ITL is illuminated to indicate occupancy of section IT. Furthermore, when this train moving to the'right vacates section IT, the apparatus is restored to its normal position in the manner already explained.

Assuming next that the signal 4S is operated to its proceed indication for a traiiic movement from track F, the repeater relay 4GP is deenergized and released when the signal 4S is set at its proceed indication, and repeater relay 4GPP is in turn deenergized and released at the end of its slow release period. During the interval relay'4GP is released and relay 4GPP is picked up, indication current ofpositive polarity flows from terminal B of battery H3 through front contact 4l of relay 4GPP, back Contact 4S of relay SGP, front contacts 33'and 34 of relays SGP and ITR, respectively, line wire LI,v asymmetric unit I5, winding of relay EGK, wire I4 and common return wire to terminal C of battery FB and the indication relay ZGK is energized. With relay' ZGK picked up, polar relay GKP is operated to close its normal polarcontact and the slow acting relay GKPP is energized but is not at once picked up due to its slow pick-up period. The slow release period of relay 4GPP is less than the slow pick-up period of relayGKPP, and hence relay 4GPP is released to open 'front contact 41 and discontinue the supply of indication current of positive polarity prior to the picking up of relay GKPP. With both relays vIIGPand 4GPPV released, the

indication current is coded to be alternately positive and negative in polarity due to the action'of coder CD, terminal B of battery FB being connected to line wire LI through coder contact 'I5- 15a, back contacts 49 and 48 of relays 4GPP and 4GP, and front contacts 33 and 34'of relays BGP and ITR; and terminal N of battery FB being connected to line wire LI through coder'contact'15-15b and the previously traced circuit connection. Both indication relays ZGK and SGK are now energized and picked up and a circuit is formed from terminal B of battery OB through front contacts 35 and 4I of relays 2GK and IiGrK, respectively, lamp 4L, back contact' of relay GKPP, normal polar contact lil-23 of relay GKP and terminal N of battery OB, and lamp 4L is illuminated to indicate the proceed indication of signal 4S. Hence signal 4S is indicated by an indication current that is momentarily of positive polarity and then coded to be 'alternately positive and negative in polarity.

' When the train on track F advances past signal 4S and enters section IT to shunt track relay ITB., the signal 4S is restored to its stop indication and relay 4GP is reenergized, and thesupply of coded indication current is discontinued.

However, indication current of negative polarity4 manner previously explained, with the result that i indication relay SGK is retained energized and relay 2GK is deenergized and released causing polark relay GEIQ3 to be operated to its reverse position. Slow acting relay GKPP is also energized but before the end of its slow pick-up period the track repeater relay ITP is released causing coded indication current to be supplied to the circuit so that both indication relays ZGK and SGK are again energized and picked up, and the relay GKPP is no longer energized. With both relay 2GK and SGK picked up, polar relay GKP operated to its reverse position and relay GKPP released, the indication lamp ITL is illuminated to indicate occupancy of the track section IT in the manner explained hereinbefore.

Itis to be seen, therefore, that any one of these four forms of indication current can be supplied to the circuit to control a corresponding indicator at the ofnce. and that the form of indication current can be changed from any one form to any one of the other forms and a corresponding change of indicators will be accomplished. Indication apparatus of the arrangement here disclosed has the advantage that four different indications can be transmitted over a single twowire line circuit with standard types of relays.

Although I have herein shown and described but one form of indication apparatus embodying my invention, it is understood that various changes and modications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention. Having thus described my invention, what I claim is:

1. In combination with an office and a station connected by a line circuit, a source of direct current at said station, a rst and a second device at said station and each operable to a rst and a second condition and each device governing a slow acting relay according to its condition; a coder at said station, circuit means including contacts of said coder and contacts governed by said devices and said slow acting relays to supply from said source to said line circuit non-coded current -of positive polarity for a predetermined interval followed by coded current alternately positive and negative impolarity and non-coded current of negative polarityfor a predetermined interval followed by coded current alternately positive and negative in polarity in response to the second condition of the rst and second devices respectively, oflice indication means including a polar relay and a code responsive-means to receive current from said line circuit and differently responsive to said two forms of current thus supplied to the line circuit at said station,

2. In combination with an oflice and a station connected by a line circuit, a source of direct current at said station, a first and-a second device at said station each operable to a first and a second condition, a slow acting relay governed by said second device, circuit means controlled by said first device to connect said source to said circuit to supply non-coded current of a preselected polarity in response to the second condition of the first device, a coder at said station, other circuit means including contacts of said coder and contacts controlled by said second device and by said slow acting relay to connect said source to said circuit to supply non-coded current of a preselected polarity for a predetermined interval followed by coded current alternately positive and negative in polarity in response to the second condition of the second device, cnice relay means connected to said circuit and differently responsive to the polarity of the current received and to non-coded and coded current, and oflice indication means governed by said oflice relay means to display-one indication in response to the second condition of said first device and to display a second indication in response to the second condition of the second device because of said different forms of current supplied to the line circuit.

3. In combination with an office and a station connected by a line circuit, a source of direct current at said station, a first and a second device at said station each operable to a first and a second condition, a slow acting relay governed by said second device, circuit means controlled by said rst device to connect said source to said circuit to supply non-coded current of a preselected polarity in response to the second condition of the first device, other circuit means including a coder controlled by said second device and by said slow acting relay to connect said source to said circuit to supply non-coded current of a preselected polarity for a predetermined interval followed by coded current alternately positive and negative in polarityin response to the second condition of the second device, a pair of office indication relays a rst one being connected to said line circuit through a nrst asymmetric unit and the second one being connected to the line circuit through a second asymmetric unit, said asymmetric units disposed reverse to each other to energize said first relay in response to current of said preselected polarity and to energize both relays in response to said coded current, a slow pick-up relay controlled by the indication relays to be energized when said first indication relay is energized but not when both indication relays are energized, a first indicator supplied with current through a front contact of said slow pick-up relay, and a second indicator Supplied with current through front contacts in series of said indication relays. Y f

in combination with a railway track switch having three signals and a track section associated therewith, a repeater relay for each of said signals energized when and only when the respective signal indicates stop, a track circuit including a track relay for said section, two slow release repeater relays one governed by said track relay and one governed by a selected one of said signal repeater relays, a source of direct current and a coder at said switch, a remote office, a twowire line circuit extending from the switch to said oflice, a first circuit means including a back Contact of a iirst one of said signal repeater relays to connect said source to said circuit to supply current of positive polarity, a second circuit means including a back contact of a second one of said signal repeater relays to connect said source to said circuit to supply current of negative polarity, a third circuit means including contacts of said track relay and of its repeater relay and of said coder to connect said source to said circuit to supply current of positive polarity during the slow release period of the track repeater relay and then coded current alternately positive and negative in polarity, a fourth circuit means including contacts of said one signal repeater relay and its repeater relay and of said coder to connect the current source to said circuit to supply current of negative polarity during the slow release period of the last mentioned repeater relay and then coded current alternately positive and negative in lpolarity, and office indication means receiving current from said circuit and characterized to respond diierently for each of said different forms of current thus supplied to said line circuit at said switch.

5. In combination, a iirst and a second indication relay each connected to a line circuit through an asymmetric unit, the two asymmetric units being disposed reverse to each other, a polar relay reversibly energized by alternative circuits one including in series a front contact of said rst relay and a back contact of said second relay and the other circuit including in series a front Contact of said second relay and a back contact of said rst relay, a slow pick-up relay energized by alternative circuits one including in series a front' Contact of said rst relay and a back contact of said second relay and the other circuit including in series a front contact of said second relay and a back contact of said first relay; a first indicator controlled through a front contact of said ilrst relay, a front contact of said slow pick-up relay and a normal polar contact of said polar relay; a Second indicator controlled through a front Contact of said second relay, a front contact of said slow pick-up relay, and a reverse polar contact of said polar relay; a third indicator controlled through a front contact of each of said rst and second relays and a normal polar contact of said polar relay; a fourth indicator controlled through a front contact of each of said iirst and second relays and a reverse polar contact of said polar relay; and supply means to supply to said line circuit steady current of positive polarity, or steady current of negative polarity, or momentary current of positive polarity followed by current alternately positive and negative in polarity or momentary current of negative polarity followed by current alternately positive and negative in polarity.

6. In combination, an office and a station connected by a two-wire line circuit, a source of direct current and a coder at said station, four devices at said station, four repeater relays one controlled by each of said devices, two slow release relays one controlled by each of two preselected ones of said repeater relays, a first circuit means including contacts oi one of the two preselected relays and its slow release relay and contacts of said coder to connect said source to said line circuit to supply current of positive polarity during the slow release period of that slow release relay and then coded current altere nately positive and negative in polarity, a second circuit means including contacts oi the other one of said preselected relays and its slow release relay and contacts of said coder to connect said source to said line circuit to supply current of negative polarity during the slow release period of that slow release relay and then coded current alternately positive and negative in polarity, a third circuit means including a contact of a third one of the repeater relays to connect said source to said line circuit to supply steady current of positive polarity, a fourth circuit means including a contactof the fourth one of said repeater relays to connect said source to said line circuit to supply steady current of negative polarity, two office relays connected across the line circuit through asymmetric units with said units disposed reverse to each other, a polar relay and a slow pick-up relay each controlled by said oiice relays, four oiiice indicators one for each of said devices; and oce circuit means including contacts of said office relays, said polar relay and said slow pick-up relay to selectively control said indicators in response to the currents supplied by said four circuit means.

EARL M. ALLEN. 

